Dual function solid state relay

ABSTRACT

A dual function solid state relay for a motor control includes four solid state switches and 6 terminals, wherein a set of 2 switches are for up operation allowing a current flow through a load in one direction and the other set of 2 switches are for down operation allowing the current flow through the load in he opposite direction. Out of 2 switches during up operation, one switch connects V+ to one end of the load and the other switch connects a Ground to the other end of the load.  
     During down operation mode, the operation is similar to the up operation except that the voltage polarities connected to the each end of the load is reversed. Out of 6 terminals, 2 are for up and down inputs and 2 are for the outputs and the remaining 2 are for V+ connection and Ground connection. With the addition of input signal control circuit to the dual functional solid state relay, a reversible solid state control device can be produced. The reversible solid state control device requires only one input signal from a push button switch for the both, up and down, operations. Structures of various silicon power switches are shown to connect power supply and Ground connections electronically to a load circuit.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] Not applicable.

MICROFICHE APPENDIX

[0002] Not appendix.

BACKGROUND OF THE INVENTION

[0003] This invention is regarding to automotive accessory or low voltage industrial motor control relays; door lock relay, power window control relay, power seat control relay, antenna control relay, cassette motor control relay, disk control motors, and more. However, for the illustrative and clarity purpose, a general purpose relay control system is explained as an example with up and down input signal notation.

[0004] Therefore, this invention is not limited only to a specific function, but extended to all relay applications described previously.

[0005] In a conventional dual function motor control system, 2 separate relays, one for up and the other one for down functions, are assembled together in a package as a dual functional relay device. One relay is activated by the up input signal from a up switch and the other relay is activated by the down input signal from a down switch.

[0006] The conventional electromechanical relay has several mechanical metal contacts, which are prone to be corroded because of heavy current passing through the contacts when the relay is energized.

[0007]FIG. 2 shows the structure of a conventional reversible motor control relay circuit. If either up or down switch is pressed, heavy current is flowing through the respective coil, energizing the relay. The coil electron current is flowing from the relay Ground (1), through coil, point (5), up switch contact, 20A fuse, to V+. The up function motor starts from the Ground (1), Ground side contact of the down relay, point (3), reversible control motor (150), point (4); activated side of the up relay 30A fuse, to V+.

[0008] The manufacturing process for a mechanical device is, in general, more difficult than that of an electronic device. For a conventional motor control relay, it requires quite heavy coil current to activate the relay.

[0009] To improve such an inherent deficiencies of the electromechanical relay, the solid state relay has been developed for many different applications. However, the most of them are functionally limited to single pole single throw switch mode. In general, those used in computer related system are low power and low voltage relays and those used in industrial application are mostly high voltage high power solid state relays. Most automotive relays should be capable of controlling devices with low voltage and high current load. Therefore, the products of this invention can be mostly utilized for the automotive and also for computer applications.

SUMMARY OF THE INVENTION

[0010] In a industrial application of a relay device, it is a general trend to replace a electromechanical relay to a solid state relay because the latter has the features of the better durability, less power consumption and easier manufacturing process. As explained in the background section, the operation of a general purpose relay control system is described for the illustrative only and its application is extended to all applicable accessory control devices. With the advantageous solid state internal structure, a dual function solid state relay of the present invention has the same functionality and external connection features as those of the conventional electromechanical relays for the respective operations. The product of the present invention can easily replace conventional dual function relays without any modification for the interconnections with the existing related devices or circuits.

[0011] The new invention provides 6 terminals, 2 for the up and down input signals, 1 for V+ connection, and 1 for Ground connection, and 2 for the output connected to the respective motor. The internal structure of the new invention includes 4 semiconductor switches, 2 for the up function and remaining 2 for the down function. Each function requires 2 semiconductor switches, 1 for power supply connection, 1 for Ground connection to the control motor of the respective function. Each semiconductor switch is made of solid state devices, either transistors, FETs, SCRs, or combination of the several those devices. The arrangement of the solid state devices of a semiconductor switch is either Darlington structure, SCR structure, driver and power transistor combination, or single power device arrangement. With the addition of the input signal control circuit to the dual function solid state relay device, it produces the composite device of the reversible solid state control device. The structures for the 2 low voltage, high power semiconductor switches, 1) Selectable input Power Switch for Positive output (SPSP), 2) Selectable input Power Switch for Negative output (SPSN), are also explained. When activated, those switches drop much less voltage across the switch devices than SCR or Darlington devices. Accordingly, they consume much less powers and generate less heat.

BRIEF DESCRIPTION OF THE DRAWING

[0012] The present invention will be more clearly appreciated from the following detailed descriptions of the present embodiments, with reference to the accompanying drawings, in which:

[0013]FIG. 1 is a block diagram showing the present embodiment of a dual function solid state relay.

[0014]FIG. 2 is a wiring diagram of a conventional dual function relay system.

[0015]FIG. 3 is an another block diagram, which is same as FIG. 1 in terms of functionality and numbering scheme. This figure will help in appreciating the function of the dual function solid state relay.

[0016]FIG. 4 is a block diagram of another embodiment of the reversible solid state control device, which is the composite of the dual function solid state relay and input switch control circuit.

[0017]FIG. 5 shows a Darlington configuration which has high current gain.

[0018]FIG. 6 shows SCR configuration which has high current capability.

[0019]FIG. 7 shows a Selectable input Power Switch for Positive output (SPSP).

[0020]FIG. 8 shows a Selectable input Power Switch for Negative output (SPSN)

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0021]FIG. 2 shows a conventional motor control system. According to the drawing, the function and structure of the prior art can be easily appreciated, are fully explained in the background section of this embodiment.

[0022]FIG. 1 represents the structural diagram of this dual function solid state relay.

[0023]FIG. 3 is shown in aiding to follow the functional explanation of the present embodiment. Therefore, for the structural view of this embodiment, refer to FIG. 1, and for the functional understanding, refer to FIG. 3. For both, FIG. 1 and FIG. 3, the numbering schemes are the same. Inside the dotted line (100) represents the block diagram of 4 semiconductor switches, SW1(10), SW2 (20), SW3 (30), and SW4 (40), which represent the dual functional solid state relay portion of the present invention. When the function switch (60) is to the up position, point (5) caries V+ to the inputs of SW1 (10) and SW2 (20) and activates them, connecting V+ to point (4) through SW1 (10), and Ground (1) to point (3) through SW2. At this time, the complete electron current path is from the Ground (1), through SW2 (20), point (3), the function control motors (150), point (4), SW1 (10), 30A fuse, to V+. Therefore, during the up operation, the current flows from point (3) toward point (4) through the function control motor. When the function switch (60) is flipped to the down position, point (6) carries V+ voltage and activates SW3 (30) and SW4 (40), connecting V+ to point (3) through SW4 (40), and the Ground (1) to point (4) through SW3 (30). At this time, the complete electron current path is from the Ground (1), through SW3 (30), point (4), the function control motors (150), point (3), SW4 (40), 30A fuse, to V+. During the down operation, the current flows from point (4) toward point (3) through the function control motor. It is evident that the current directions through the function motor are just opposite between up operation and down operation. This proves that the four switching means provide proper voltages polarities for both up and down operations.

[0024]FIG. 4 shows a reversible solid state control system (300), which includes input switch control circuit (200), and dual function solid state relay (100) that has been described in the previous section in detail. Every time the input SW (60) is pushed, positive pulse is applied to the input of the FLIP FLOP (80), which, in turn, toggles the outputs on the Q and Q′. Between Q and Q′ outputs, one is high level and the other one is low level for any given input. For the next arrived input pulse, the states of Q and Q′ are changing to the opposite states respectively from the previous ones. According to the diagram shown, Q output is used as up control signal and Q′ output is used as down control signal. For an example, if the input SW (60) is momentarily pressed, the positive pulse will trigger the FLIP FLOP, causing Q output high (assumption), and Q′ output low. The output of A1 (70) is also high, and activates SW1 (10) and SW2 (20) by allowing the current flow through the function control motor (150). The electron current path starts from Ground (1), through SW2 (20), point (3), the function control motors (150), point (4), SW1 (10), to V+. If the same SW (60) is pushed again momentarily, it toggles the FLIP FLOP (80), changing Q output to low level, and Q′ output high level, accordingly A2 (71) output is high level, point (8) is high level, and SW3 (30) and SW4 (40) are activated. The action allows down function current flow through the function control motor (150), starting from Ground (1), SW3 (30), point (4), the control motors (150), point (3), SW4 (40), to V+. This description explain that the up function current flow path through the control motor (150) is just opposite from that of the down function operation. The purpose of two AND gates (A1, A2) are as following; the input signal control circuit (200) is so designed that the control motor is moved to up position by default upon the starting the car. At this time, Q output is at high level and Q′ output is at low level. However, the both outputs of A1 (70) and A2 (71) are at low level because the input SW (60) remains open state. The input SW (60) is momentarily closing switch. If the function is to be down, press the input switch (60), then Q output is low and Q′ output is high, while the door SW (60) is being pressed, point (6) and point (9) maintains high levels, affecting A1 output low and A2 output high, activating SW3 (30) and SW4 (40). This action will move the motor to down position. While in the down position, release the input switch, then both AND gate outputs are low level and deactivate SW3 (30), SW4 (40), causing all 4 semiconductor switch outputs floating.

[0025]FIG. 5 is a typical Darlington transistor configuration, which provides high current gain and is employed in many high gain amplifier application. However, it can be adopted for the power witching application in a circuit which has low power supply voltage and demands high current output.

[0026]FIG. 6 is a typical SCR configuration, which is capable of high current gain and high output current. It drops approximately 1 volt across the ANODE (1) and the CATHODE (3), but can be used in a switching application.

[0027]FIG. 7 and FIG. 8 represent low voltage high power switches.

[0028]FIG. 7 is a Selectable input Power Switch Positive output (SPSP) circuit. This device drops very low voltage across it, and connects the remaining power supply voltage to a load circuit. This is a positive or negative selectable input activated device, and comprised with a NPN driver (6), a PNP power transistor (5), a diode (7) and 5 terminals. The 2 gate terminal are connected to the input terminals through current limiting resistors. When a positive input is applied to the driver, NPN transistor (6) drives the PNP silicon power transistor (5) with high driving current, closing the switch and connecting the V+ to a load circuit. Terminal (4) is the unique element for this configuration. The terminal is connected to a Ground. The current limiting resistor (R1) is connected between points 8 and 9 with terminal (4) connected directly to the Ground. Because of this arrangement, the voltage drop between the ANODE (1) and CATHODE (3) of the poker transistor is very small. The diode (7) is for rectifying the high voltage spike generated by the load, keeping the voltage on point(3) less than or equal to V+ when the switch is turned off. The circuit can be used as a positive only triggered device by eliminating GATE2 terminal. By disconnecting the NPN driver circuit, the device can be used as a negative only triggered switch.

[0029]FIG. 8 is a Selectable input Power Switch with Negative output (SPSN) circuit. This device drops very small voltage across it, and connects a Ground to a load circuit. This is also a positive or negative selectable input activated device, and comprised with a PNP driver transistor (6), a NPN power transistor (5), 2 current limiting resistors, bleeder resistor, a diode (7), and 5 terminals. The 2 gate terminals are connected to the input terminals through current limiting resistors. When negative input is applied, PNP driver transistor(6) drives the NPN silicon power transistor (5) with high driving current, closing the switch and connecting the Ground to a load circuit. When GATE1 is connected to V+, the switch is also activated and the Ground is connected to the Load. Terminal (4) is the unique element for this configuration. The terminal (4) is connected to a V+.

[0030] The current limiting resistor (R₁), is connected between points 8 and 9 with terminal (4) connected directly to the V+. Because of this arrangement, the voltage drop between the ANODE (1) and CATHODE (3) of the power transistor is very small. The diode (7) is for rectifying the high voltage spike generated by the load when the switch is turned off The resistor R₃ is a bleeder resistor which discharges the residual voltage left across the power transistor after turned off. This negative output semiconductor power switch is activated by either negative or positive input signals.

[0031] By eliminating GATE1 terminal, the circuit can be used as a negative input triggered switching device. The device can also be used as only positive triggered switch by eliminating PNP driver circuit.

[0032] In its broader aspects, this invention is not limited to the specific embodiment illustrated and described. Those skilled in the art may make various changes and modifications without departing from the scope and spirit of the present invention. It is the expressed intention of this invention to embrace all such changes and modifications which fall within the scope of the described claims thereby. 

What is claimed is:
 1. A dual function solid state relay apparatus for controlling a reversible motor, comprising: 4 semiconductor switching means defined as first, second, third, and fourth switches for two motor control functions, one for the up control function and the other one for the down control function, wherein 2 semiconductor switching means are required for each function; and 6 terminals, wherein the first terminal is for Ground connection, the second one is for V+ connection, the third one is for one polarity of power supply output, the fourth one is for the other polarity of power supply output, the fifth one is for the up control input signal, and the sixth one for the down control input signal.
 2. A dual function solid state relay apparatus according to claim 1, wherein first and second semiconductor switching means are used for the up control function, first switch for the connection of V+ terminal to one end of the control motor, second switch for providing Ground connection to the other end of the control motor.
 3. A dual function solid state relay apparatus according to claim 1, wherein the third and the fourth semiconductor switching means are used for the down control function, the fourth switch for the connection of V+ terminal to one end of the control motor, the third switch for the connection of the Ground terminal to the other end of the control motor.
 4. A dual function solid state relay apparatus according to claim 1, wherein semiconductor switch means comprising: Darlington transistors; or power MOSFETs.
 5. A dual function solid state relay apparatus according to claim 1, wherein semiconductor switch means comprising Silicon Controlled Rectifiers.
 6. A dual function solid state relay apparatus according to claim 1, wherein semiconductor switch means comprising: a) A Selectable input Power Switch for Positive output, defined as SPSP, further comprising: a PNP silicon power transistor; a NPN driver; a rectifier diode; current limiting resistor; GATE resistor; and 5 terminals, wherein, GATE1 is connected to a positive input, GATE2 is connected to a negative input, ANODE is connected to V+, CATHODE is connected to a Load, and CONTROL terminal is connected to a Ground. The current limiting resistor is connected between the base of the power transistor and the collector of the driver. For positive input only feature, the GATE2 terminal is eliminated. For negative input only feature, the NPN driver circuit is eliminated. b) A selectable input Power Switch for Negative output, defined as SPSN, further comprising: a NPN silicon power transistor; a PNP driver; a rectifier diode; a bleeder resister; current limiting resistor; GATE resistor; and 5 terminals wherein GATE1 is connected to a positive input, GATE2 is connected to a negative input, CATHODE is connected to Ground, ANODE is connected to a Load, and CONTROL terminal is connected to a V+. The current limiting resistor is connected between collector of the driver and base of the power transistor. For positive input only feature, PNP driver circuit is eliminated. For negatively feature, GATE1 terminal is eliminated.
 7. Complementary pair of semiconductor power switch devices for connecting V+ and Ground terminals to a control motor in a low voltage, high power circuit, comprising: a) A Selectable input Power Switch for Positive output, defined as SPSP, further comprising: a PNP silicon power transistor; a NPN driver; a rectifier diode; current limiting resistor; GATE resistor; and 5 terminals, wherein, GATE1 is connected to a positive input, GATE2 is connected to a negative input, ANODE is connected to V+, CATHODE is connected to a Load, and CONTROL terminal is connected to a Ground. The current limiting resistor is connected between the base of the power transistor and the collector of the driver. For positive input only feature, the GATE2 terminal is eliminated. For negative input only feature, the NPN driver circuit is eliminated. b) A selectable input Power Switch for Negative output, defined as SPSN, further comprising: a NPN silicon transistor; a PNP driver; a rectifier diode; a bleeder resister; current limiting resistor; GATE resistor; and 5 terminals wherein GATE1 is connected to a positive input, GATE2 is connected to a negative input, CATHODE is connected to Ground, ANODE is connected to a Load, and CONTROL terminal is connected to a V+. The current limiting resistor is connected between collector of the driver and base of the power transistor. For positive input only feature, PNP driver circuit is eliminated. For negative input only feature, GATE1 terminal is eliminated.
 8. A reversible solid state control device for controlling a motor, comprising: four semiconductor switch means, defined as first, second, third, and fourth switches; five terminals, the first terminal is for Ground connection, the second one is for V+ connection, the third and the fourth ones are for outputs, and the fifth one is for input control signal; and an input signal control circuits.
 9. A reversible solid state control device according to claim 8, wherein 2 semiconductor switch means, the first switch and the second switch, are used for the up control function, the first switch is for providing the connection of V+ terminal to one end of the reversible control motor, the second switch is for providing Ground connection to the other end of the reversible control motor.
 10. A reversible solid state control device of claim 8, wherein 2 semiconductor switch means, the third switch and the fourth switch, are used for the down control function, the fourth switch is for the connection of V+ terminal to one end of the control motor, the third switch is for Ground connection to the other end of the control motor.
 11. A reversible solid state control device according to claim 8, wherein the input signal control circuit comprising: a FLIP FLOP for producing 2 toggled outputs Q and Q′ with one trigger input signal from the input signal switch; and two AND gates.
 12. A input signal control circuit according to claim 11, wherein the first AND gate receives 2 inputs, the first input is from the input switch, the second one is from Q output of the FLIP FLOP, and produces the up control signal connected to the up control input of the dual function solid state relay, the second AND gate receives 2 inputs, the first input is from the input switch and the second one is from output of the FLIP FLOP, and produces the down control signal connected to the down control imput of the dual function control solid state relay. 